In this tutorial we’ll updating/installing Kernel 4.17 on Linux OS – Centos 7. So what is kernel? -A kernel is the lowest level of easily replaceable software that interfaces with the hardware in your computer/server. It is responsible for interfacing all of your applications that are running in “user mode” down to the physical hardware, and allowing processes, known as servers, to get information from each other using inter-process communication (IPC).